Heat transfer



April 18, 1961 G A E 2,980,403

HEAT TRANSFER Original Filed May 16, 1951 4 Sheets-Sheet 1 INVENTQR.

ATTORNEY April 8, 1961 K. G. AHLEN 2,980,403

HEAT TRANSFER Original Filed May 16, 1951 4 Sheets-Sheet 2 April 18, 1961 5 AH E 2,980,403

HEAT TRANSFER Original Filed May 16, 1951 4 Sheets-Sheet 3 if Fig.9.

Fig.11.

AQ/ "ix- ATTORNEY K. G. AHLEN HEAT TRANSFER April 18, 1961 4 Sheets-Shegt 4 Original Filed May 16, 1951 R. .m. n W. HM

TEN

OON

. in: connection with the air rates HEAT TRANSFER Km-l Gustav :ahln, Stockholm, Sweden, assignor to Svenska Rotor Maskinir Aktiebolag, Necka, Sweden, a corporation of Sweden 3 Claims. (Cl. 257-241) This application is a division of my copending application Serial No. 226,582, filed May 16, 1951, now U.S. Patent No. 2,874,940, granted February 24, 1959, and relates back thereto as to all dates and rights incident to the filing thereof. 7

The present invention relates to heat transfer and in its broader aspects has reference to heat transfer between a solid body and a fluid medium. More specifically, the invention relates to heat transfer between a solid body and a gaseous fluid medium and still more particularly the invention relates to indirect heat exchange between two different fluids, either or both of which may be liquid or gaseous, by heat transfer to and from the different fluids and a solid body with which the fluids are separately in surface contact.

The general object of the invention is to provide for heat exchange at high rates of transfer per unit area of heat exchanging surface, to provide for such transfer with minimum expenditure of power for effecting relative movement between the heat exchanging bodies and in certain of its aspects to utilize movement of the solid heat exchanging body to create, in whole or in part, the required flow of the fluid or fluids with which the solid body is in heat exchange relation.

In order to attain the above generally stated objects and other and more detailed object hereinafter appearing, the invention contemplates the provision of a rotating solid body in the form of a rotor having a multiplicity of circular fins or ribs with intervening channels in the form of grooves concentric with the axis of rotation of the rotor, with which there is associated a rotationally stationary structure having baflle members projecting into the grooves and cover means for the grooves for controlling flow of fluid in the grooves, such structure further being combined with means providing transfer passages for conducting fluid to and from different grooves in accordance with novel principles hereinafter more fully described, which result in a novel character of flow which is productive of the improved results sought by the invention.

The invention'is particularly adapted for heat exchange between two gaseous fluids for purposes such as the pre- 2,980,403 Patented Apr. 18, 19161 from its use, reference may best be had to the ensuing portion of this specification, taken in conjunction with the accompanying drawings forming a part hereof, in which: I

Fig. l is a more or less diagrammatic longitudinal section, on line 1-1 of Fig. 2, of an air preheating apparatus embodying the principles of the invention;

Fig. 2 is a fragmentary cross-section taken on the line 2-2 of Fig. l;

Fig. 3 is a fragmentary plan View taken on line 33 of Fig. 2, and with certain elements indicated in phantom for the sake of clarity;

Fig. 4 is a fragmentary perspective view of part of the structure shown in the preceding figures and with certain elements omitted for the sake of clarity;

Fig. 5 is a view, similar to Fig. 3, showing a different structural arrangement of certain of the parts for producing an altered character of fluid flow;

Fig. 6 is a fragmentary cross-section taken on the line 66 of Fig. 5;

Fig. 7 is a fragmentary perspective'view, similar to Fig. I

4, of the arrangement shown in Fig. 5;

Fig. 8 is a view similar to Figs. 3 and 5 showing an other arrangement of structure for producing fluid flow of different character. than that shown in Figs. 3 and 5;

Fig. 9 is a fragmentary cross-section taken on line 99 of Fig. 8;

Fig. 10 is a fragmentary longitudinal section taken on line 1010 of Fig. 8;

Fig. 11 is a view similar to Fig. 8, showing structure providing an altered character of fluid flow as compared with that of Fig. 8;

Fig. 12 is a longitudinal section similar to Fig. 1 showing apparatus embodying the invention and having a different form of rotor than that shown in Fig. l; and Fig. 13 is a fragmentary cross-section taken on the line 1313 of Fig. 12.

Referring now more particularly to Figs. 1 to 4, the apparatus comprises a rotor indicated generally at 10, having a shaft part 12 and a hollow drum 14 defined by a radial end wall 16, a cylindrical wall. 18 and a second radial wall 20. The cylindrical wall 18 carries a multiplicity of external axial-ly. spaced radial fins or ribs 22, providing between thema multiplicity of external annular channels or grooves 24. The drum'further carries a multiplicity of similar internal ribs 26 providing a multiplicityof internal annular grooves 28.

Associated with the rotor there is provided a rotationally stationarystructure comprising a hollow drumlike internal casing member indicated generally at 30. Mem ber 30 is mounted coaxially with the rotor and has a cylindrical casing wall 32 radially spaced from the inner heating of airto be used for combustiornby waste heat 7 extracted from combustion gases exhausted from apparatus such as power boilers and internal combustion'engines and gas turbines. The invention will therefore be described hereinafter, by way of example but without limitation, as applied to air preheating structure, but it will be understood that the principles of theinv'ention are susceptible of use in many other applications and that for certain of such applications, the principles of the invention in its broader aspects may be carried out-with only certain features of the structure hereinafter described preheater apparatus chosen by wayofexample. .7 1- a For a better understanding of the more detailed nature of the invention, the manner in which if-may be carried 7 into practical effect, and theadvantages to be derived 5 8 which communicates fwithi an inlet 34 atone end and outlets 36 at the other end;

The stationaryjstructur'e further comprises an outer drumlike casing wall. 38 surrounding the rotor and radially spaced from the external ribs 22. The stationary-structure further has end walls 40 and 42, the former'extending inwardly past the end wall 16 of the rotorto shaft part 12of'the rotor where a-seal 41 maybe employed,

1 and the latter extending inwardly to therinletaportion 34 v of member 30. An inlet ductf44;for fluidcommunicates 'by way of opening 46-at; one end of the rotor with the space 48 between rotor wall 18 fand the outer, casing 38.

This space communicates-at the -oth er' end of the rotor by way ofan opening 49 with the outlets SO andfSZ, The wall'54' extends inwardly to. a seal diagrammatically indicated at 56 and with wall 42 providihg anoutlet duct h thel'slpace 69 between the rotor wall '118 and Wall321of manner 30 In "thefembodiment off apparatus" illu "te the fluids, as for'example air to' be heated; enters'theinemand flows ber fl'through the an" 34 in the direction of arrows 62 through member 30. From this space the air 7 and opening 46 to the spacei48 between the rotor drum to 18 and the outer casing wall 38, The gas flows generally from left to right as viewed in Fig. .1 through this pace in amanner hereinafter to be described and through opening 50 to the outlet duct 52'.

The wall 32 of member 30 carr esa'plurality of baffie members 66 extending axially o f=the "rotor and peripherally spaced around the circumference of wall 32, These members are of comb-like form having a multiplicity of fingers 68 projecting into and substantially filling the crosssections of the grooves28. Similar comb-like baffle mem- 2Q bers 70 extend inwardly from the outer casing wall 38 and are provided with fingers 72 substantially filling the cross-sections of the externalrotor groovesi2 4. a

spaced relationfbetween. the 'bafile'members 70, 'a pluclearly-seen from Fig. 3. These partitions extend periph to the adjacentbafiles and divide thespacesbetween the Figs. 3 and'4; These ports provide communication be- Externally of the ribs 22 and located peripherally in rality of cover members 74 extend axially in closely spaced relationto the crests of the ribs '22. These cover members are supported by means of partition 'or.guidev plates 7,6"carried by'the casing wall 38, as will be more erally frornone baflle to the next end comprise oblique; central portions 78 overlying the cover members 74' and transverse end portions80. The end porti9ns80 of.these partitions extend 'beyond the edges of the cover members edges of the'cover plates andthe baffles intotwo series of axially aligned ports betweeneaeh two adjacentbafflesi Oneseries of such ports is indicated at $2, 82a, 82b.aud 82c, and the other is indicated at 84,8411, 84b and 84c, in

tween thesectorso'f the grooves 24 between the'adjacent 'bafil'es and the spacebetween the baffies which lies radially outside the'cover 'members. or plates the. latter space being divided by the partitions into ;a series of oblique {transfer passages; as indicated at 86,, 86a, 86b* and-86c in Figs. 3 and 4, these passages being defined by the cover" plate 74,'the radially outer parts 10," the. outer casing 'wall 38-and the partitions; 1 I V 1, v 'Ra'dially inside th" rotor drum; 1. asimilar structure'- is provided comprising cover plates 88 disposed iadjacent tothe crests of the inner ribs'26 and series oh partitions or guidei plates-90 for jsupporting the cover plates and forming series 'of'ports 9 21 and $4, andtogether with the 'cfo'ver plates. 88; the inner :casing w'ell 32 and, "adjacent- 'to the rotor axis.-

inner bafl les 66 providing obliquetransfer passages', 96 similar to passag'e 86. ,TransferpassagesSQ and 9 6'dilfer in thatthey are oblique iuoppositeldirections with respect ii a e operation 'o f the aparat s desfibea followsi Q 5 reaches the discharge end of the rotor and from Fig. 4 it will be evident that the ga's'column entering port 82, which is divided into individual streams in the grooves, travels in what may be saidto be a generally helical path "to flow along the rotor between two adjacent baffies. "From the precedingdescription, it will be obvious that peripherally of the rotor there will be a series of such gas columns each confined between two adjacent bafiies and moving. in 'generally helical paths along the rotor.

The action with respect to flow through the grooves between the inner flanges 26 is the same as being described and for the apparatus assumed, the air en'ters through duct 34 and is divided into anumber of air columns each flowing between adjacent baflles in a generally helical path along the rotor to the outlet duct 58. f

Whileboth thegas and the air flow peripherally in the direction of the rotor, while in the grooves, it will be evident from Fig. lthat the gene'ral flow relation between the two fluids is counterflow, the hottest gasbeingfin heat exchange relation ,with'thatpart-of the. rotor in contact with thehottest air and the coolest gas being in heat exchange relationwith that partof the rotor to which the l coolest enteringair is admitted. I I

u The action of the apparatus has been described above as applied to theipreheating of combustion. air by com- 7 bustion gases and in such application it is ordinarily preferable to pass the gases through the external groovesof the drums and the airthrough the internal grooves since I the. volume of gas'passing through the apparatusinsuch applications is usually larger .thanthe volume of air. Also, the external fgroov'e structure isemore readily cleaned of Qsolids-such as soot andash deposited by the'relatively dirty combustiongases. Insoafter as the basic operation is concerned, it will, however, beievide nt that if desired the hot medium may be passed through the internal.

grooves, and the medium to be heatedPaSsedthIough the externalgrooves, the choice being governed by the nature and characteristics of the media" employed and the de- 5 sired heatexchang e between them. 1 I 5 i V As is;well;known, the rate of heat transfer between a fluid and a solid body is, among other things, a function of H the relative velocitybetweenthetwoand by the present l arrangement: a highv relative velocity betweenv the rotor and the gaseous fl uids can readily be maintained. Also, by limiting the n nt rrupted flowof the fluids in individual grooves to sectors ofpr edetermine'd, length, the character of-the flow can becontrolledso as to produce a high 1 rate of heattransfer notionlyibecause, of highrelative velocity, but also. because of'the fact ;th'at the absolute velocity of me fluid c'an'be maintained atia sufiiciently 5-low value, to prevent turbulence of an' undesired nature. e I helve qcityi 'u ici t y-,,l0w,;ge e a y; l m r fl can be maintained'exceptat thesurface layersewhere small secondary; eddies rotating; about;;axe s porrnal'to the gent eraljlineof; flowlare produced Thesejeddies-are desirable Considering-firstl'the gas'entering through du'ct .44 and m g i ff heat-transfer'amdido; not create ening 46, this gas enters'rai ial groupof grooves24 I much, resistance: to flow, andsinc'e th iagr are Pref in,tlie directionfindicated by arrow 98in Fig between the gas and the surfaeeiof the through inlet ports j 82=. distributed. around theperiphery of the structure. @Itgbeing assuin'ed thatthe roto turning fr c n moving ribs causes the; cover plate Qerablygenerally relatively deep and narrow the eddy like turbulence, of the surfacev layersjssutficient 'to bring most 1 of the fluid, stream into heat exchange contact vwith the 5 1solid surface, ,If the stream ina givengrpove is permitted tqbeacceleratedto too' greata'n absoluteyelocity, :so that 7 j its jveloeityjrelative to 'thatzof the walls of the groove is v 1ow,"by beingIpermit tedlto trayel'toolong a 'p'ath'in'a given .g q notronlyiisthetemperature differencegandithe rate V jojof heatgtransfe accordinglyreduced hmalsofitheremay be induc ed .aiIQt l'Y'turbulenceiimtheiplane "of rotation,

' which isuridesirable. *Furthegbyejecting theifluid from 3 the; grooves after :a predetermined;lengtheof travel and V V ;;transferring,; he fluid{toanothenisetrof grooves, it .is furcolumn is brought into intimate heat exchange relation with heat transfer surface.

The number, spacing and cross-sectional shape and areaof the grooves may vary widely depending upon the nature of the heat exchange conditions to be met, the character of the fluid or fluids involved, entering temperatures and desired leaving temperatures, volumes to be handled, pressures and other specific factors. These factors will also affect the length of the paths of flow of the streams in individual grooves, the grouping of the grooves, which may, for example be such in an extreme case that each group may consist of but a single groove. In the embodiment being described the grooves have, for the sake of simplicity, been shown of equal cross section between equally spaced ribs. It will be evident, however, that in cases where a gas is materially cooled and contracts materially during its flow through the appa fatu's, and it is desired to maintain a relatively constant velocity of flow, the ribs may be spaced closer together at the colder end than at the hot end to compensate for the contraction.

Also, in apparatus where the path of flow is relatively long and through a large number of groove sectors, the cumulative eifect of the friction may result in a higher than desired velocity through the apparatus when a given fluid column travels in all cases through the grooves in the direction of movement of the rotor, as illustrated for example inFig'. 4. This condition can readily be avoided by apparatus operativeto reverse the direction of flow in any selected number of sectors so that in such sectors the fluid flow in the grooves is counter to the direction of movement of the rotor and in Figs. to 7, one suitable embodiment of apparatus for effecting this is illustrated. In substantially all particulars the arrangement is the same as that previously described and corresponding parts are correspondingly numbered. The difference between the constructions is that any selected space, or spaces,- as

shown more particularly in Figs. 5 and 7, the direction of slant of the oblique portion 78 of the partition members 76 is iever sed as indicated at 78a so that if we compare Figs. 3 and 5, and Figs. 4 and 7, respectively, it will be seen that the. fluid flowing from the grooves through outlet 'port 84a, flows axially in the arrangement of Figs.

5, and-7 to inlet port 82b, which is in effect an axial continuation of the outlet port 84a. From inlet port 82!), the fluid flows through the grooves counter to the direction of rotor movement to outlet port 84b which in this em- 7 bodiment, is on the same side of the cover member 74 as the inlet ports 82 and 82a. In the embodiment illustrated, the counter flow is carried through a plurality of groups of grooves, but it will be evident that this specific arrangement may be varied at will with respect to the number and arrangement of passes through the grooves in which the fluid flows counter to the direction of rotor rotation, as compared with the passes in which the flow is in the samedirection. In any case, it will be. apparent that in those passes where the flow is counter to the direction of rotor rotation, friction will exert a decelerating effect and by proper selection for a given designthe rate. of flowof fluid through the apparatus as a whole may readily be governed to suit the specific conditions. 7

As noted above, the grooves are preferably relatively' fde'ep and narrow and the ratio of depth to width of "the grooves may in many instances be'as much'as ten re one, or even' materially greater. With-such relatively deep and narrow grooves, the rate of heat transfer'in the grooves is improved by the provisionof auxiliary guidefin gers shown at 102 and 104m Fig. 2. which fingers extend only'partially of the full depth of the p groovesand are located so that they serve to divide and guide the fluid entering and leaving the groove sectors the bafile members 70' and supported in any suitable fashion as parts of the stationary structure, it being noted that in the present embodiment these guide members must be radially spaced from the cylindrical walls 32 and 38, respectively, of the stationary structure since the fluid must flow across the tops of these guide members in its flow between the several ports and the transfer passages. For the sake of clarity, these guide members have been shown in phantom view in .Fig. 3 and have been omitted from the showing in Fig. 4. The number and specific arrangements of the guide fingers at any particular port or series of ports may be varied to suit the individual conditions required in order to obtain a more advantageous distribution of flow of the fluid throughout the depth of the groove.

Also in certain instances it may be desirable to provide inlet ports of greater peripheral extent than that of the outlet ports, rather than ports of equal area as shown in the apparatus illustrated.

It will further be apparent from the nature of the apparatus described that in addition to acting as a heat exchanger the apparatus may also provide all of the power required to create the flow of the fluid media and for example when used as an air preheater may provide the only means required to produce the necessary forced draft flow of the combustion air and also the force required to exhaust the spent combustion gases. Thus the apparatus may enable separate forced draft and exhaust fans to be eliminated entirely, or materially reduce the power requirements for such fans by acting as a compound fan for both purposes.

In both of the embodiments above described, the stationary structure is arranged so that the fluid columns flow in generally axial direction from end to end of the rotors. T his arrangement, however, may be varied and in Figs. 8 to 10, another embodiment is illustrated in which a different path of flow for the air columns is provided. In this example, the general arrangement of rotor and stationary structure areas shown in Fig. 1, and corresponding parts are similarly designated. In the present. construction, the baflie members providing the fingers extending into the grooves, do not extend from end to end of the rotor but are peripherally offset as indicated at 7a; b, 70c, 70d and 702 in Fig. 8. Each of these offset baffies is coextensive with a group of grooves, the

number of which may be chosen at will, axially coextensive with the bafiles. A series of sets of box-like cover members 1il6and 108, the bottoms of which provide respectively the cover members 74 and 88 located respectively over the inner and outer rotor grooves. The end walls 110 and 112 of these box-like members define peripherally the limits of the inlet and outlet ports communicating with the groove sectors while the side walls 114 and 116 define the axial extent of the ports. Due

to. the peripherally offset relation of adjacent ones of the several series of the box members the outlet ports communicate with one group of grooves which are axially in communication with the inlet ports of the next adjacent group of grooves by wayof axially extending transferpassages 118, each defined by abafile member, the

side walls of two of the adjacent box members, the inner or outer casing wall 32 or 38 as the case may be.

From Fig. 8, the nature of the flow of the fluid columns indicated by arrow's 120,;fr0m which it will be seen that the several columns progress successively through peripherally offsetsectors of axially successive groups of groovesgthe general direction of the path of flow being helical around the rotor drum rather than generally axithrough the "respective inlet and outlet ports. These ally thereof, as in the arrangement shown in Fig.1.

In the present arrangement, auxiliary-guide fingers 192 I and 104 are shown and-it will be noted that in thepresent constructionthese fiuide fingers can be extended for sup-- "portbythe casing parts 38 and 32, respectively, since the flow through the transfer passage is lengthwise'of these v iguide members rather-than across thegtops of them,as'1in :the previously described embodiments. 7 I j In thearrangernentshown'in Fig. 8,' the fluid flow in the grooves. is always in the direction of movement of the rotor and for reasons previously explained it may be desirable to provide for counter flow of the fluid in one or more groups of grooves. An arrangement for effecting this is shown in Fig; 11, wherein certain of thebaflie memberst70 and box members 106" are shown'in oifse't relation such that the direction of how of the fluid col:

umns is peripherally reversed as indicated by arrows 122.

a In'Figs.;l2 and' 13, the invention is shown embodied in a'rotortof-differentform than that shown in the. previously described embodiments.

In this form "of the apparatus the rotor shaft 200 carries a radially extending disc 202'which in turn supports a multiplicity of radially spaced concentric cylindrical ribs 204 'a'n'dj206 on the opposite sides of the disc respectively and providing a multiplicity of annular cylin- 'dric'al' channels of groove-like form 208 and 210, respec- -tivel'y. The stationary structure indicated ar 212 com-t i prises an 'outer'cylindric'al sheli 214 between'which and disc 202 a seal diagrammatically indicated at 216 is provided, andfe'nd wall s 218 and 220. Thestructure'forms an inlet duct 222 for fluid such as air to be heated, which 7 communicates with the; annular space 224 immediately around the rotorshaft on-oneside of the disc=202.' The structure further provides an outletduct 226 having an annular I portion 228 extending around the'periphery of thecasin'g adjacent to theend wall 220 and the flow of air from duct :222 to 226 is generally outward from the at" greater radius, as seen more clearly in Fig l-3, a n d i between adjacent baflies of each 'set' areb'ox-like, cover "members'234 which are likewise in' sets,' with adjacent qi peripherally ofiset" relative to 7 These cover membersf234 aref sirnilar in r im a'nd t function 'to the-box-like jcover members illustrated, in Fig. i l 8, ahd have-side walls defining inlet'and outlet ports 236 V and l 23 8 communicating 'with' the sectors of the' grooves betweenadjacent'bafiies of the same'fsetl -As furtherwill be s'een from Fig. 13, therelative peripheral locationot the 'cover. members of the adjacent sets issuch that the t inlet ports'leading to one group of grooves is-radially V 1 in registry with'af group-o f outlet ports leadingfrorn a- "radially adjacent set of grooves, to provide radially exj tending transfer passages 240 forkcarrying "fluid ;disharged from the: sectors. of} one group of grooves to pe- 7 ripher'ally oifset s'ectdrsjof the adjacent-group of grooves flying radially outside the' gr'oup from whichIthe fluid 'is un harged. 7

By comparison of'Figsslil and 8, itf will a Fthatthe-arrangement is the s ame:ini,pr1nciple in b theidifi'erence being that; the seyeral-column sof ifluid i "the arrangement. of Figi l3 fiow'fin generali y spiral'dir i s t i 5"; apparatusawithinithe b tweenthearra emen att e two s d Qt t e 020.1 being that in onecase the fluid flow isin generally out ward dir'ectionwhile in the'other-case the flow is in gen ;e'rally spiraljinward directionto the outletduct 255., As

"5 -,in the previous Yembodirnentgthis arrangement pro vides tor counter flow;j Preferably,--asdescribed; the fluid to 'be heated; which expands, flows-outwardly, while; the heating fluid'whi'ch contracts due to being 'cooled flows inwardly.

'10 It will be evident thatt'iu the just described,

"the arrangement of the baffles and the cover members i-maybetmade so to provide flow of fluid counter to the direction of rotation of the rotor infas many asthesectors a s'isdesiredin order-toprovide the;desired;rate of 115 yflowl 'rVaria'tion in relative size of inlet and outlet ports and the provision of auxiliary guide fingers are, for the sake of clarity, 'omitteditrom-th'efigures. Qtherjeatures .;of design previously 'described may;equal'lywell be applied to'thejem'bodiment underconsideration; Y

' 1" In all ofthe previously'described embodimentgimovement of the rotating'body is utilized to indujcetflow of the flllid.'01ifilllld$j and the rotary-movement of thejfluid, and :sfolidbodies'isconcurrent;

However,*the basic princrplesi of thefinvention are 25 equally applicable, with improved results,-, in cases; where in'order' to secure an-evenhig her rateof-he at'transfer bettweenfluid'and solidbodies, thefluidisforced by mechanlical: means such 'as a ian" to flow gcount er to' the direction ofrotation of-thesolidbody; For such'amethod'o'f oper- 0 tation; i is evident that the structures 'hereinbefoi'e described; except torithemodiflcations illustrated; inil figs.

' 5;: and t1 are s bl :w th utr eg i qn being required thatappropriate fan; or equivalent means of any z desired conventional kind be providedto etfe'ct thejneces- 5 saw flow offluid in the direction'opposite that indicated ;by the'arrows inthe-several figures, 1

operative'with forced" flow; counter 3 to the direction of -rotation of the solid body, but 1in;suqh ca fi ihe reversal 'ofxflow at-intermediate places efiectedby'these struc- :t r u d e v -n9 u e ul P IPQS a d wou i detrimentalr A i V jj perfici lly, it m ht; bl affi if i itd no q fi e eto..the,direction*of rotation'ofi'the solid bodyisrat var i- '45; 'c 'w h/ e basic p i c p e of he t Yqnfi awa d- 7 beforeidescribed, but;such;:is ;not the case, .since relative :veloeities between the iheaLexchanging bodies i may -besecured with relatively lowabsolute velocities of thePfluid bodies, Lowabsolute velocity'oi the fluid avoids ,in the planeot rotation,hereinbeiqre; discussed, even rthoughthe jrelative velocityr-between the fluid, andsolid bodies =is}fhigh.-j This, together with there; that tin j; 'for' thejrate:of -heat exchange o btajnegl; W il rip po e o aexp a n nsy he i pa tus has been law nv or; eete g au ,p t s ous fluidsgboth 'o twh h re sed d w a novel principles of tlie invention," ittw ill be tliunderstood; that-such principlesare equally applicable for vention, ap-

"elu n fall; i e m V 9 What is claimed: 1. Heat exchange apparatus comprising a rotor having a radially extending disc-like central wall, a plurality of radially spaced circular ribs concentric with the axis of rotation of the rotor extending from the opposite sides of said central wall to provide on each side of the central wall a series of circumferentially continuous open groove-like circular channels concentric with the axis of rotation of the rotor, stationary structure including inlet and outlet openings for fluid media and having end walls facing respective ends of said rotor and cooperating with said rotor to provide for flow of fluid media in paths of flow in said channels between said openings lying in planes normal to said axis, said stationary structure including radial baffles, certain of said bafiles having one radial edge abutting one of said end walls and the others of said baflies having one radial edge abutting the other of said end walls and the opposite longitudinal edges of said batfles having fingers extending into and obstructing said channels, arcuately extending cover means for said channels disposed between adjacent baffles, means forming transfer passages connecting different channels at places adjacent to said baflies and at opposite sides of said cover means for flow of fluid media progressively through different channels on each side of said central wall, and means to drive said rotor.

2. Heat exchange apparatus comprising a rotor having a radially extending disc-like central wall, a plurality of radially spaced circular ribs concentric with the axis of rotation of the rotor extending from the opposite sides of said central wall to provide on each side of the central wall a series of circumferentially continuous open groove-like circular channels concentric with the axis of rotation of the rotor, stationary structure including inlet and outlet openings for fluid media and having end walls facing respective ends of said rotor and cooperating with said rotor to provide for flow of fluid media in paths of flow in said channels between said openings lying in planes normal to said axis, said stationary structure including a plurality of radial circumferentially spaced baflles, certain of said baflies having one radial edge abutting one of said end walls and the others of said baflies having one radial edge abutting the other of said end walls and the opposite radial edges of said baflles having fingers extending into and obstructing each 4 of said channels to divide the same into a plurality of sections, arcuately extending cover means for said channels disposed between adjacent balfles, means forming transfer passages connecting different sections of said channels at places adjacent to said baffles and at opposite sides of said cover means for flow of fluid media on each side of said central wall progressively through peripherally displaced sections of different channels on the same side of said central wall, and means to drive said rotor.

3. Heat exchange apparatus comprising a rotor disc having a plurality of circumferentially continuous open circular groove-like channels concentric with the axis of rotation of the disc and providing for flow of fluid media in paths of flow in said channels lying in planes normal to said axis, said channels comprising a first series of front channels extending axially outwardly from one side of the disc and a second series of rear channels extending axially outwardly from the other side of the disc with said disc defining the bottoms of both series of channels, stationary structure including inlet and outlet openings for fluid media and having front and rear walls concentric with and cooperating with said disc to provide for flow of fluid media in paths of flow in said front and rear channels between said openings, said stationary structure including radial front and rear baflles, said front baflies having one radial edge abutting said front wall and the opposite radial edge having fingers extending into and obstructing said front channels, said rear baflies having one radial edge abutting said rear Wall and the opposite radial edge having fingers extending into and obstructing said rear channels, arcuately extending front and rear cover members for said front and rear channels disposed between adjacent front baflles and between adjacent rear bafiies, means providing front transfer passages connecting different front channels at places adjacent said front baifles at opposite sides of said front cover means for flow of a first fluid medium progressively through different channels of said first series, means providing rear transfer passages connecting different rear channels at places adjacent said rear baflles at opposite sides of said rear cover means for flow of a second fluid medium progressively through different channels of said second series, and means to drive said rotor disc. 7

Ellsworth et al. Aug. 15, 1933 Vannerus June 18, 1946 

